Apparatus for excavation of deep holes and trenches

ABSTRACT

This disclosure relates to an apparatus for the excavation of deep holes and trenches, which comprises a grab bucket whose jaws are carried by a rigid rotatable support bar and are connected by a pair of arms to a sleeve member which is screwed onto a threaded end portion of said support bar.

[ Feb. 8, 11972 Patent Motto [56] References Cited UNITED STATES mums Olson.....................................175/202 Giuseppe Bette, c/o Costruzioni Cemento 2,203,246 6/1940 Zum-Berge :...175/238 x ...175/23s x Compresso Fondisa S.p.A. Corso Europa 2,499,508 3/1950 Karhu 2,645,458 7/1953 3,113,629 12/1963 3 194,329 7/ l 965 11, Milan, Italy .llan. 16,1969

Appl. No.: 791,701

Yost.....

[22] Filed:

Allard...... ...l75/238 Wallers..............................l75/238 X Primary Examiner--David H. Brown 1 1 Fwugn Application Priority Dam Attorney-Guido Modiano and Albert Josif [57] ABSTRACT This disclosure relates to an apparatus for the excavation of deep holes and trenches, which comprises a grab bucket Italy............................. ...22880 A/68 [51] int. ....lE2llb 27/00 175/238, 202, 173; 37/183 whose jaws are carried by a rigid rotatable support bar and are connected by a pair of arms to a sleeve member which is screwed onto a threaded end portion of said support bar.

[58] Field of Search 1 Claims, 3 Drawing llfigum PATENIED FEB 8 I972 IN VENTOR. ppe BOTTO Giuse BY APPARATUS FOR EXCAVATION Oil" DEIEIP ll-llOlLlES AND 'IRENCHIES BACKGROUND OF THE INVENTION The present invention relates to an apparatus for the excavation of holes and trenches of considerable depth.

Many two-jaw apparatuses (in general grab buckets) are presently known for the excavation both of deep holes and trenches either opencast or in ambient of stabilizing fluids, for example, bentonite fluids, the opening and closing of such apparatus being controlled by means of a tackle arrangement actuated by cables which are controlled from above by means of suitable winches or hydraulic pistons controlled from the surface through a fluid-operated unit connected to the pistons by means of a suitable flexible tubing.

Grab jaw apparatuses are also known whose jaws are actuated by hydraulic pistons fed by a fluid-operated unit with an electric motor housed in the same apparatus. In this case the feeding of power to the motor occurs through an electric cable.

Such apparatuses are not, however, free from disadvantages, among which may be noted a not completely satisfactory earth penetration capacity of the grab bucket; a limitation of the power which may be transmitted to the grab bucket because of the connections of the latter with the control members; the difficulty of controlling the vertical relationship of the excavation, during the carrying out thereof, so that it has been necessary to employ expedients such as, for example, that of connecting the grab bucket to a rigid structure.

The main object of the present invention is that of obviating the above-mentioned disadvantages by providing an apparatus for the excavation of deep holes and trenches in which the earth penetration capacity of the grab bucket is increased, wherein it is possible to transmit powers to the grab bucket which are considerably higher than those permitted by the apparatuses of known type, and still enables the vertical relationship of the excavation to be controlled during operation, particularly when excavations are carried out of trenches with vertical walls rendered stable for instance by the presence of bentonite-type muds.

SUMMARY OF THE INVENTION According to the invention there is provided an apparatus for the excavation of holes and trenches of considerable depth, characterized in that it comprises a grab bucket whose jaws are carried by a rigid rotatable support bar and are equally secured to said bar by a mechanical coupling designed to cause to opening and closing of the jaws due to the rotation of said rigid bar.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will appear more clearly from the following description of a preferred embodiment of an apparatus according to the invention, illustrated by way of example in the accompanying drawing, in which:

FIG. 1 diagrammatically shows such apparatus wherein the grab bucket has jaws of rectangular cross section;

FIG. 2 shows in plan view a casing which covers the grab bucket;

FIG. 3 shows a modification of the apparatus in its embodiment with grab bucket having circular section jaws.

With reference to said figures, the apparatus comprises an supporting arm 1 for raising the grab bucket and at the upper end of the arm there is suspended a rigid bar 2 which may be rotated by a rotatable plate 3. The lower end portion of the bar 2 is threaded in 4 and at the end of the bar is idly mounted a supporting member on which the jaws 5 of the grab bucket are pivoted. Such jaws are also connected, through rod members or arms 6, to a nut screw or internally threaded sleeve member 7 which is screwed onto the threaded portion 4 of the bar 2, thus providing a screw and nut screw coupling.

The torque applied to the screw is counteracted, in the case of a rectangular section grab bucket (FIG. 1), by the ground through a casrng 8 whose surface IS such as to reduce the stresses on the walls of the excavation to always acceptable values irrespective of the nature of the ground.

In the case of a grab bucket having jaws of circular section conventional means engage the walls of the hole and form an adequate reaction due to friction to said torque.

During the closing action of the jaws during excavation, the entire weight of the rigid bar 2 acts on the grab bucket and actuates the latter, thus considerably increasing the earth penetration capacity of the grab bucket. Besides this it is possible, through the rigid bar, to transmit powers considerably above those permitted by the systems in use until now. Further, due to the rigid connection between the grab bucket and the control bar it is possible to control the vertical relationship of the excavation during the carrying out thereof.

I claim:

ll. An apparatus for the excavation of holes and trenches of considerable depth, comprising a supporting arm, a rigid rotatable bar holded at one end of said arm, means for rotating said rotatable bar, a supporting member arranged at the lower end of said rotatable bar in a nonrigid connection relationship therewith, a multijaw grab bucket having at least two jaws pivotally connected to said supporting member and capable of oscillating around a substantially horizontal axis, rod means having one end pivotally connected to said jaws of said grab bucket for actuating the opening and closing thereof and means for locking the apparatus against rotation during excavating operations inside said holes or trenches, wherein according to the improvement, the apparatus further comprises a threaded portion provided on the lower end length of said rotatable bar adjacent said supporting member, the length of said threaded portion being at least equal to the vertical movement component of said one end of said rod means, an internally threaded sleeve member engaging with the said threaded portion of said rotatable bar and pivotally holding the said rod means at the other end thereof, said rod means preventing rotation of said sleeve member with respect to said supporting member, whereby the rotation of said rotatable bar causes said sleeve member to move along said threaded portion of said rotatable bar effecting the opening and closing of said jaws of said grab bucket in the excavating operation. 

1. An apparatus for the excavation of holes and trenches of considerable depth, comprising a supporting arm, a rigid rotatable bar holded at one end of said arm, means for rotating said rotatable bar, a supporting member arranged at the lower end of said rotatable bar in a nonrigid connection relationship therewith, a multijaw grab bucket having at least two jaws pivotally connected to said supporting member and capable of oscillating around a substantially horizontal axis, rod means having one end pivotally connected to said jaws of said grab bucket for actuating the opening and closing thereof and means for locking the apparatus against rotation during excavating operations inside said holes or trenches, wherein according to the improvement, the apparatus further comprises a threaded portion provided on the lower end length of said rotatable bar adjacent said supporting member, the length of said threaded portion being at least equal to the vertical movement component of said one end of said rod means, an internally threaded sleeve member engaging with the said threaded portion of said rotatable bar and pivotally holding the said rod means at the other end thereof, said rod means preventing rotation of said sleeve member with respect to said supporting member, whereby the rotation of said rotatable bar causes said sleeve member to move along said threaded portion of said rotatable bar effecting the opening and closing of said jaws of said grab bucket in the excavating operation. 